Yes. But probably not the way you think.

If you’ve tried a warm-up tool and still ended up in spam, you’re not alone. Most of the agencies I speak to have either skipped warm-up entirely or run it for two weeks, seen no dramatic change, and assumed it wasn’t working. Both of those approaches will cost you.

Email warm-up does work. But its effectiveness depends almost entirely on three things: how long you run it, which tool you use, and how closely it matches your actual sending behaviour. Get those right, and it transforms your inbox placement. Get them wrong, and you’re paying for the illusion of progress.

This guide explains how warm-up works mechanically, why recruitment agencies have a harder time than most, and which tools are worth your time.

What Email Warm-Up Actually Does

Warm-up is the process of gradually building your sending reputation with inbox providers like Gmail, Outlook, and Yahoo. When you send from a brand-new domain – or one that’s been flagged for poor engagement – those providers have no record of how your emails perform. No history means no trust.

Warm-up tools solve this by simulating real email activity. They send from your actual domain, deliver to a range of real inboxes, generate replies, mark your emails as important or starred, and pull any that land in spam back into the inbox. The result is a growing body of evidence that tells Gmail: this is a legitimate sender, with a real audience, whose emails get read.

Without that foundation, your first real campaign is flying blind into a reputation vacuum. It won’t necessarily get blocked. It’ll get silently deprioritised – tabs, promotions folders, occasionally spam – with no error message to tell you why.

Why Recruitment Agencies Need to Warm Up More Carefully Than Most

Most email warm-up guides are written for SaaS founders sending newsletters. Recruitment agencies have a fundamentally different problem. Here’s what makes you harder to warm up:

You send cold. Recruitment outreach – whether to candidates or hiring managers – is almost always unsolicited. That means lower engagement rates by default. Inbox providers factor engagement into reputation scoring, and your warm-up signal has to be strong enough to compensate.:
Your volumes spike. A quiet week, then a campaign to 500 candidates. Inbox providers notice irregular patterns and treat them as suspicious until you’ve built enough history to justify them. Warm-up establishes that pattern as normal before you hit send.:
You’re often on young domains. Whether you’ve recently rebranded, set up a cold outreach subdomain, or switched to a dedicated sending domain on the advice of your CRM provider, new domains are treated as guilty until proven innocent.:
Your list quality is variable. Recruitment databases – especially older ones pulled from LinkedIn or legacy CRM exports – often contain stale email addresses. High bounce rates damage reputation faster than almost anything else.:

Running warm-up properly, over at least 90 days for a fresh domain, is the only way to get ahead of these factors rather than constantly chasing your tail.

The Two Types of Warm-Up Tool

There are two broad approaches, and they suit different situations.

Community-based tools (like Lemwarm)

These connect you to a network of other users’ mailboxes. Your emails get sent to community members, and theirs get sent to you. You reply to each other, star messages, and drag things out of spam – all automatically.

They’re low cost, effective for B2B cold email, and good at simulating the kind of real-person behaviour that Gmail pays attention to. The limitation is reach: most community networks are heavily weighted towards small business mailboxes. If your candidates use consumer Gmail or Apple Mail addresses, the warm-up signal is less relevant to those inbox types.

Best for: agencies doing B2B outreach or running cold email to business contacts at moderate volumes.

Network-based tools (like Warmy.io)

These use a proprietary internal network – often a mix of verified mailboxes and AI-driven behaviour – to warm up your domain across a wider range of inbox types. Gmail, Outlook, Yahoo, and Apple Mail all get covered with more realistic diversity of behaviour.

The trade-off is cost and transparency. You’re often paying more, and it can be harder to verify exactly what’s happening behind the scenes. But for agencies sending at scale, or warming up a domain used for both candidate and client outreach, the broader coverage is worth it.

Best for: agencies sending at volume, targeting a mix of consumer and business email addresses, or recovering a damaged domain reputation.

Best Email Warm-Up Tools for Recruitment Agencies

Tool	Type	Best use case	Recruitment fit	Est. price
Mailreach	Community	B2B cold email	Good for agency-to-client and BD outreach	~$29/mo
Warmy.io	Network	Broad coverage, B2C mix, high volume	Strong for outreach at scale	~$49/mo
Instantly	Network + community	Getting a low use domain off the ground	Popular with recruiters	~$37/mo
Smartlead	Network	Sales outreach sequences	All-rounder for recruitment campaigns	~$39/mo
Mailwarm	Community	Budget warm-up for small senders	Basic coverage; fine for small teams starting out	~$19/mo

* Prices are approximate and change frequently. Check current plans before committing.

No tool is a silver bullet. At Quinset, we regularly recommend different tools to different agencies based on their sending volumes, CRM setup, and audience split. If you want a recommendation for your specific situation, get in touch.

How Long Does Warm-Up Actually Take for a Recruitment Agency?

The honest answer: longer than you want it to.

For a brand-new domain with no sending history, expect at least 90 days before your reputation is stable enough for meaningful cold outreach. For a damaged domain recovering from poor engagement or spam complaints, the timeline is similar – sometimes longer, depending on how bad the damage is.

Phase	Volume	What to do
Days 1–30	10–20 emails/day	No live campaigns. Focus purely on replies and engagement. Run daily inbox placement checks.
Days 31–60	40–60 emails/day	Vary subject lines and reply patterns. Monitor domain reputation in Google Postmaster Tools.
Days 61–90	100–150 emails/day	Scale based on reputation signals. If Postmaster shows high or medium reputation, you’re on track.
After Day 90	Campaigns + warm-up	Start campaigns with your most engaged segment first. Keep warm-up running in the background – permanently.

One thing recruitment agencies consistently get wrong: they stop warm-up the moment they start sending campaigns. That’s exactly when you need it most. Warm-up isn’t a one-time fix – it’s an ongoing protection layer that keeps your reputation stable while you send.

Can You Do This Without a Tool?

Yes, but it’s slow and requires discipline. Manual warm-up means sending a small number of real emails each day from your new domain, encouraging replies, asking recipients to mark you as ‘not spam’ if you land in junk, and running regular inbox placement tests to track your progress.

It works if you’re patient, have the technical knowledge to monitor your results properly, and have a small pool of genuinely engaged contacts to start with. Most recruitment agencies don’t have that combination readily available – which is why warm-up tools exist. They automate the job and make it safer and faster.

What to Watch Out For

Never send live campaigns from a domain that hasn’t been warmed up, regardless of how urgent the brief is.
Never start with high volumes and try to warm up while sending simultaneously.
Be sceptical of any tool that promises inbox placement guarantees within days. Good reputation takes time to build and can’t be faked convincingly at speed.
Check whether a tool’s network sends to its own users almost exclusively. If your emails only ever reach other tool users, the signal quality is limited. Look for genuine inbox diversity.
Watch out for tools that show impressive-looking dashboard metrics without letting you verify actual inbox placement independently. Use Mail-Tester or GlockApps to cross-check.

Need a Warm-Up Plan Built Around Your Agency?

At Quinset, we help recruitment agencies and recruitment technology providers warm up their domains the right way. We match the tool to your audience, structure the ramp-up schedule around your campaign calendar, and monitor performance until you’re sending with confidence.

If your emails are going quiet (landing in spam, sitting in promotions, or simply not being opened) we can tell you why. Get in touch and we’ll take a look.